Typographic matrix and method of making the same



M. C. INDAHL.

TYPOGRAPHIC MATRIX AND METHOD 0s MAKING THE SAME.

APPLICATION FILED MAR. 31; I920.

Patented Dec. 21,1920.

FIG-5- FIG. 1- FIG; 2.

INVENTOR 1 Na/urziz Cfizda/zl, BY a a? HIS ATTOR NEY.

UNITED STATES PATENT OFFICE.

MONO'IYPE MACHINE COMPANY, RATION 0F VIRGINIA.

0F PHILADELPHIA, PENNSYLVANIA, A CORPO- TYPOGRAPHIC IIIATRIX AND METHOD OF MAKING THE SAME.

Specification of Letters Patent.

Patented Dec. 21, 1920.

Application filed March 31, 1920. Serial No. 370,285;

To all whom it may concern:

Be it known that I, MAURITZ C. INDAHL, a citizen of the United States, residing at Philadelphia, county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Typographic Matrices and Methods of Making the Same; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this speci fication, and to the characters of reference marked thereon.

This invention relates to typographic matrices of the kind commonly known as cellular matrices for use in connection with the improved casting and composing machines well known as manufactured and sold by Lanston Monotype Machine Company and the general organization of which is disclosed, for example, in Letters Patent No. 625,998 dated May 80, 1899.

The said cellular matrix consists of a parallelopiped-shaped block of brass, bronze or the like with a cone hole in one end for centering the matrix over the mold, the opposite end forming the surface against which the type is cast and being usually impressed with a character depression to form the raised character defining portion of the type. The block is rectangular in section and its four sides are grooved, two opposite sides having wide grooves to accommodate the backs of the combs used in retaining matrices in a matrix case and the other two sides having narrow grooves for the teeth of said combs. The matrix, the combs and the case are all standard parts of the improved machine above referred to and are well known to those skilled in the art but reference may be had also particularly to Letters Patent No. 784,245, dated March 7, 1905, which shows clearly the three parts.

The manufacture of said matrices comprises among other operations suitably preparing the matrix block, impressing the character, drilling the cone hole and cutting the side grooves. The latter operation consists as practised heretofore in first milling a plain bevel on each of the four corners of the sides of the block,.intermediate its ends, the length of the bevels corresponding with the width of the wider grooves, and then milling the wide and narrow grooves. Although the beveling operatlon has for its purpose preventing chips, fins or burs clinging to the matrix as the result of the grooving, it was found'in practice that beveling was wholly effective only when it was so deep as materially to shorten the bearing length of the combs. The difficulty will be more clearly set forth hereinafter in connection with the description of the invention with the aid of the drawings. It will be noted that the beveling and grooving are from a commercial and manufacturing standpoint conveniently milling operations. They may be carried out by the use of special machines such as the matrix beveling machine disclosed in Letters Patent N 0. 1,008,304, dated N ovember 14, 1911 and the matrix grooving machine disclosed in Letters Patent N 0. 980,903 dated January 10, 1911.

The principal object of the present inventron is to produce a matrix without clinging chips, fins, burs or the like projecting beyond the side groovebottoms and having substantially the maximum length of comb bearing surface such a matrix having serrated bevel portions separating the bottoms of adjoining grooves. Its object is also to provide a method of manufacture by which a serrated bevel is formed, followed by the usual grooving so that a chip formed in advance of the grooving tool is out toward the points of the serrations and is cleanly removed because its attachment to the block gradually decreases until these points are reached, after which, as the tool proceeds, there is no attachment whatever. Other objects and advantages will hereinafter be pointed out or will otherwise appear in connection with the following description of the invention as illustrated in the accompanying drawings in which:

Figure l is an enlarged perspective view of the matrix block ready for beveling and grooving.

Fig. 2 is a similar view showing the block after the beveling peration.

Fig. 3 is a similar view showing the finished matrix.

Fig. 4 is an enlarged plan view of several matrices assembled in supporting combs, portions being broken away to show a matrix in cross section on substantially the line 4-4 of Fig. 3, and

Fig. 5 is a similar view showing in cross section a matrix produced in accordance with the method disclosed in the beveling and grooving machine patents above mentioned.

The matrix block 1 shown in Fig. 1 is provided with a centering cone hole 2 and may be assumed to have passed through the usual operations preparatory to beveling and grooving. The beveling operation produces the partly finished matrix 1" shown in Fig. 2. The beveling cut acts upon the four side corners of the matrix and may be accomplished in any suitable manner. The upper portion 3 of each bevel, as shown in Fig. 2, is a flat out making equal angles with the sides of the matrix. The lower portion 4: of each bevel is serrated to form ridges or teeth and, between them, ditches or depressions, extending crosswise of the matrix. The serrated bevel 4 is cut deeper than the plain bevel 3 so that it serves as the terminus of two grooving cuts at right angles to each other. The beveling may conveniently be accomplished by the use of the patented beveling machine previously referred to, the only change necessary being the provision of milling tools having stepped plain and serrated cutting portions.

The finished matrix 1 SllOWIl in Fig. 3 is made from the partly finished matrix of Fig. 2 principally by subjecting such partly finished matrix to the grooving operation. This operation may be performed in any suitable manner, conveniently by milling the grooves by the use of the patented grooving machine above mentioned. This operation provides the wide grooves 5 on opposite sides of the matrix and the narrow grooves 6 on the other matrix sides. The width of the Wire grooves is sufficient to accommodate the backs 7 of the supporting combs of the matrix case, and corresponds with the combined length of the plain bevel 3 and the serrated bevel 4. The narrow grooves 6 are of a width to accommodate the teeth 8 of the matrix 'case combs and correspond with the length of the serrated portion 4 of the bevels. The depth of the grooves is approximately half the width of the comb backs and teeth so that when assembled, Fig. 4, each matrix is supported on all four sides and overlaps approximately one half of the thickness of the comb parts which support it. The bottoms of the grooves terminate in the bevels 3 and 4; that is, the depth of the grooving cut is such that the bottom of the groove begins and ends in a beveled surface. The bevel cuts must themselves be deep enough to permit this as otherwise the grooving would cut the beveled surface entirely away. In the finished matrix, therefore, there is left of the bevel 3 the relative small surface 3 (Fig. 3).

The bevel 3 prevents the formation of a bur at the shoulder 9 and if there is a slight bur left clinging along the length of the bevel portion 3 it mayreadily be removed by rubbing the outside matrix surfaces along a roughened surface, such as that of a file, the rubbing movement being longitudinally with respect to the matrix since across rubbing would merely bend the bur back into the groove and would not remove it unless the bending back and forth were repeated. The portions 3' may be described as those portions of the bevels 3 which are left on the finished matrix; and since the bevels 3 form the terminal surfaces for the upper portions of the bottoms of the wide grooves 5, the bevel portions 3' may be said to separate the external surfaces of the matrix from the upper parts of the bottoms of said wide grooves.

The bottoms of the narrow grooves 6 and of the lower parts of the wide grooves 5 both terminate in the serrated bevels 4. In the finished matrix, therefore, there is left of the trapezoid-shaped surfaces of the bevels 4: the small substantially triangular shaped surfaces 4' which may be regarded as in pairs having their apexes meeting in common points '45 which form the meeting points also of the bottoms of two grooves 5 and 6 at right angles to each other. The bases of adjoining pairs of triangles 4: meet in lines 4: which are what is left of the depressions of the serrations, while the points 4 may be regarded as what is left of the ridges or teeth of the serrations of the bevels l. The triangular shaped surfaces 4: may be said to be those portions of the bevels 4 which are left after the grooving operation; and since the beveled parts 4 form the terminal surfaces for the bottoms of the narrow grooves 6 and of the lower parts of the bottoms of the wide grooves 5, the .surfaces a may be said to separate the bottoms of the narrow grooves 6 and the lower parts of the wide grooves 5.

- If it be assumed that a groove has been cut and the cutting tool is proceeding in the cutting of another groove at right angles to the first groove, there will be a chip in advance of the tool. When the tool reaches the serrations 4 the cut will resolve itself into a plurality of separated small cuts, depending upon the number of serrations, and each small cut will gradually diminish in its line of contact with the groove bottom, as the tool proceeds, until it reaches the point 4 at which it will have theoretically a point connection or attachment with the groove bottom. In other words the line of attachment of the chip is broken up into a plurality of lines when the region of serrations is reached and from then on the line of atta chment just severed is always greater than the line of attachment left and the latter is thus always decreasing. Further advance e am of the tool-will decrease the attachment-to zero and'the chip will be severed or bent to cause it to fall off. In such way the cut is aclean one and leaves no chip or bur.

It is to be noted that a bur left where the bottoms of two grooves meet cannot be rubbed off (as can a bur along the surface 3) because such a bur is hidden in the groove behind the external surfaces of the matrix and a rubbing motion longitudinally of the matrix cannot be applied. The only remedy is the bending back and forth of the bur until it falls off. This is necessarily hand work and is especially tedious when the matrix material is bronze or some other tough material. It may also be stated that burs at such point must be removed or the matrix will not fit into its cell between the comb backs and two comb teeth. The serration bevel successfully prevents the formation of these burs within the grooves and makes it unnecessary to perform any hand work on the matrices. In practice the block of Fig. 1 is passed through the serration. bevel tool equipped beveling machine referred to, the beveled matrix is passed then through the grooving machine referred to and the finished matrix is then passed between files to make certain that there are no burs 011 the outside surface and to remove any loose chips or shavings. The matrix is thereupon ready for assembly in a matrix case.

Angular cut off faces 10 between the grooves and the outside surfaces of the matrix 11 and between the serration triangles 4 and the plain bevel portions 3 are preferably formed, as shown in Figs. 2 and 8, this being conveniently done as a part of the beveling operation. These cut off corners or faces being at the beginning and the end of each groove form beveled guides for the comb teeth during the assembling operation and, besides insuring that no burs or turned over edges may be accidentally formed, especially during handling after manufacture, to partially close the grooves and diminish their full width, these faces assist considerably in facilitating the assembling operation.

It is further to be noted that, as shown particularly in Fig. 4, the points 4 of the serrations are in the planes of the external surfaces of the matrix so that in the comb they possess a maximum length of bearing surface, S, Fig. 4. The matrix therefore fits snugly in the comb cell and is held from twisting by a bearing surface on all four sides which is as long as may be. For comparison purposes there is shown in' Fig. 5 a comb with an old form of matrix 1 assembled in it, a matrix in the manufacture of which the plain beveling operation was car ried out as by the aid of the patented beveling machine without change, in contradistinction to-the present serratedbevel matrix.

3The plain beveled matrix must have the bevels, deep enough so that burs left by the jgrooving tool would be bent over upon the beveled surfaces and not extend over the bottom surfaces of the adjoining grooves. yThismeansfthat beveling is effective only if deep and consequently the matrix after grooving will have a bearing surface length S, Fig. 5, which is notably much less than the bearing length S, of the present process. The longer bearing length obviously insures greater leverage against twisting and less looseness in the cell after wear-while substantially preserving the full area of bearing surface. Thus a better lasting matrix and one more readily made and assembled is produced.

I claim 1. A method of making typographic matrices of the cellular type, comprising preparing a metal block rectangular in section with a casting face at one end and a conehole in the other end, then cutting the side corners of the block intermediate its ends to form serrated beveled surfaces and then cutting the four sides of the block to form grooves the bottoms of which terminate in the said serrated bevels, whereby a matrix is produced free of clinging burs on the bottoms of said grooves.

2. A method of making typographic matrices of the cellular type, comprising preparing a metal block rectangular in section with a casting face at one end and a conehole in the other end, then cutting the side corners of the block intermediate its ends to form stepped bevels, the shallow bevel being plain and the deep bevel being serrated, and then cutting the four sidesof the block to form wide grooves on two opposite sides and narrow grooves on the remaining two sides, the bottoms of which grooves terminate in said bevels, whereby a portion of each plain bevel is left which separates an external surface of the matrix from a portion of the bottom of one of the wide grooves, and a portion of each serrated bevel is left which separates the bottom of a narrow groove from a portion of the bottom of a wide groove.

3. A cellular typographic matrix comprising a block provided in one end with a cone hole and having a casting surface at the other end thereof, two opposite sides of the block being provided with wide grooves and the remaining two sides with narrow grooves, the bottoms of the narrow grooves and a part of the bottoms of the wide grooves being separated by serrated bevel portions, a part of the bottoms of the wide grooves and opposite external surfaces of the matrix being separated by plain bevel portions, the serrated bevels being each connected with a plain bevel by an angular cut-ofi face.

4. A cellular typographic matrix comprising a block rectangular in cross section and provided in one end with a cone-hole and having a casting surface at the other end 5 thereof, the four sides of the'blook being grooved for receiving supporting comb parts, the bottoms of adjoining grooves being separated by a serrated bevel portion comprising pairs of substantially triangular surfaces the apexes of which meet in points 10 at Which the bottoms of said grooves also meet.

MAURITZ C. INDAHL. 

